Serializable has no methods. It is a tagging interface only. From the API docs: Serializability of a class is enabled by the class implementing the java.io.Serializable interface. Classes that do not implement this interface will not have any of their state serialized or deserialized. Michael Morris
Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction. - Ernst F. Schumacher
As Michael say, Serializable has no methods. You don't have to do anything to implement Serializable (other than say you are doing it). However, if you want to control the serialization and deserialization in a different way from the default, you implement those writeObject() and readObject() methods. In practice you don't have to do that very often.